I want to grab hold of his weapon arm, keep control of it, wrestle him to the ground, and pin him there.
(Let's say my fighter knows some wrestling/jiu-jitsu. Most classical fighting styles -- even those focused on weapons -- taught an array of effective holds and takedowns.)
If I'm unarmed, and the goblin is armed, I'm in a world of trouble. That's defy danger for starters, at least (possibly just giving the goblin a free hit, depending on the situation. Trying to wrestle someone who's holding a sword or knife is stupidly dangerous. But hey, my fighter also fights dragons.)
But let's say I get a 10+ on the defy danger. Do I do it? Or do I also then roll a hack and slash, where my "damage" is wrestling? I sort of lean toward the latter, and I think that's a good catch-all case for attacks that aren't directly damaging (in the way the thrust of a blade is). AW allows for this, too, with some examples including attacks like "dragging away, 0-harm."
For cases where the skill discrepancy is large -- my fighter wants to disarm a peasant who is brandishing a kitchen knife -- then maybe it's simply one move to do it (defy danger or hack and slash) or possibly no move at all if the opponent isn't a credible threat.
Aside: evilben is totally right about damaging moves in grappling. I know lots more ways to inflict serious harm that way than by striking. I addition to jiu-jitsu, I once took combatives seminars called "UFC fouls" and "Illegal holds", both entirely focused on really dangerous stuff. :)